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Baader Hyperion eyepieces: potential problem with 1-1/4" diagonals/focusers

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Baader Hyperion eyepieces: potential problem with 1-1/4" diagonals/focusers

By Bill Wiegert

The Baader Hyperions are optically superb, good looking, and exhibit excellent finish and internal quality. Better still, their price doesn't perform open wallet surgery on the buyer. I have a 21mm, and it gets frequent use. However, there exists a minor manufacturing problem concerning the 1-1/4 inch section of the barrel.

It seems that a good quantity were made with a taper and shipped out before the problem was discovered. If you get one that is seriously tapered, you may have difficulty using it in a 1-1/4 inch diagonal or focuser that employs a compression ring. You can bypass the problem if you use it as a 2-inch.

Specifically, some of their 1-1/4 inch barrels are tapered from top-to-bottom, as much as 045-inch. I have measured two examples in which the taper was 028-inch in just the capture groove alone. This may prevent secure tightening, and in fact my 21mm easily wobbled around in the diagonal with little effort. The taper, if severe enough, can cause only minor engagement of the very top edge of a compression ring, which is not nearly enough. Not knowing what was wrong, my initial reaction to this was to tighten it up until I thought I might break something. But it remained loose and floppy. Inserting it into the 2-inch holder made it secure.

I have a way of knowing that the problem is fairly rampant. At one dealer every one in his inventory exibited the defect to a degree; some more than others. Some are severe enough that you can tell just by looking at it. This section of the barrel is generic to all focal lengths, so the problem can exist in any of them.

Again, it is potentially a problem only if you have a 1-1/4 inch diaginal or focuser employing a capture ring. The two-inch section is fine, and I would not discourage anyone from purchasing one of these optically fine eyepieces. Besides, the part in question is easily removable, and can possibly be exchanged for a good one, if the manufacturer is so inclined. I have yet to look into it because I have a 2-inch diagonal.


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